The background art of this invention is covered by many articles dealing with flow fluorometry of small particles, confocal optical microscopy, two-photon excitation, fluorescence correlation spectroscopy and single molecule detection. As background art of this invention we list the following articles relative to sensitive flow fluorometry:
Two-Photon Excitation
Denk, W., Strickler, J., and Webb, W. W. Two-photon laser microscopy. U.S. Pat. No. 5,034,613, 1991. PA0 Lytle, F. E., Dinkel, D. M., and Fisher, W. G. Trace-Level Quantiation Via Time-Resolved Two-Photon-Excited Fluorescence. Appl. Spectrosc. 47(12):2002, 1993. PA0 Denk, W, Strickler, J. H., and Webb, W. W. Two-photon laser scanning fluorescence microscopy. Science. 248:73, 1990. PA0 Sepanlak, M. J. and Yeung, E. S. Laser Two-Photon Excited Fluorescence Detection for High Pressure Liquid Chromatography. Anal.Chem. 49(11):1554-1556, 1977. PA0 Wirth, M. J. and Fatunmbi, H. O. Very-High Detectability in Two-Photon Spectroscopy. Anal.Chem 62:973-976, 1990. PA0 Nguyen, D. C. and Keller, R. A. Ultrasensitive laser-induced fluorescence detection in hydrodynamically focused flows. Journal of the Optical Society of America B 4(2):138, 1987. PA0 Mathies, R. A. and Peck, K. Laser excited confocal microscope fluorescence scanner and method. Eur. pat. appl. 91300246.5(440 342 A3), 1991. GO1N 21/64. PA0 Dovichi, N. J., Martin, J. C., Jett, J. H., Trkula, M., and Keller, R. A. Laser-Induced Fluorescence of Flowing Samples as an Approach to Single-Molecule Dectection in Liquids. Anal. Chem. 56(3):348, 1984. PA0 Lee, Y., Maus, R. G., Smith, B. W., and Winefordner, J. D. Laser-Induced Fluorescence Detection of a Single Molecule in a Capillary. Anal.Chem. 66(23):4142, 1994. PA0 Mathies, R. A. High Sensitivity Fluroerscent Single Particle and Single Molecule Detection Apparatus and Method. PCT/US90/02702(WO 90/14589), 1990, GO1N 21/64. PA0 Mathies, R. A., Peck, K., and Stryer, L. Optimization of High-Sensitivity Fluorescence Detection. Anal.Chem, 62(17):1786, 1990. PA0 Peck, K., Stryer, L., Glazer, A. N., and Mathies, R. A. Single-molecule fluorescence detection: Autocorrelation criterion and experimental realization with phycoerythrin. Proc.Natl.Acad.Sci. 86:4087, 1989. PA0 Shera, E. B. Single molecule tracking. Eu. Pat. 88909172.4(EP 0 381, 694 B1), 1988. GO1N 21/64. PA0 Shera, E. B., Seitzinger N. K., Davis, L. M., Keller, R. A, Soper, S. A., Detection of single fluorescent molecules, Chem Phys Letter 23:553-557, 1990. PA0 Dovichi, N. J., Martin, J. C., Jett, J. H., and Keller, R. A. Attogram Detection Limit for Aqueous Dye Samples by Laser-Induced Fluorescence. Science. 219:845, 1983. PA0 Rigler, R. and Eigen, M. Method and device for assessing the suitability of biopolymers. PCT/EP/00117 (WO94/16313), 1994. GO1N 21/64.
Flow Fluorometry and Cytometry
Confocal Microscopy
Single Molecule Detection
Fluorescence Correlation Spectroscopy